Heat transfer recording media

Abstract

The present invention relates to a heat transfer recording medium in which a substrate items of information such as an image and characters formed on a surface thereof by heat transfer and a transparent protective layer is provided on at least a part of the surface of the thus recorded information through an adhesive layer, if required, characterized in that the adhesive layer and/or protective layer function to provide security against counterfeiting. Combining information recorded by heat transfer with a function to provide security against counterfeiting, the present invention provides greater security against falsifying or counterfeiting.

We claim: 
     
       1. A heat transfer recording medium comprising: a substrate having items of information recorded on a surface thereof by heat transfer wherein said substrate includes an its surface a background pattern, an image and literal information, said background pattern and image printed by a heat transfer technique; and   means for providing security against counterfeiting comprising a transparent protective layer provided on at least a portion of the thus recorded surface of said substrate, said protective layer including a design layer therein or thereon which does not substantially conceal said information, said design layer comprising at least one number selected from the group consisting of a transparent pigment, a dye, a fluorescent dye, an infrared absorber, a fluorescent brightener, an ultraviolet absorber, and an oxygen indicator.   
     
     
       2. The heat transfer recording medium of claim 1, wherein said substrate is in the form of a card. 
     
     
       3. The heat transfer recording medium of claim 1, wherein said design layer formed on or in said protective layer is visually observable in a normal state. 
     
     
       4. The heat transfer recording medium of claim 1, wherein said design layer formed on or in said protective layer is not visually observable in a normal state. 
     
     
       5. The heat transfer recording medium of claim 1, wherein said protective layer comprises layers between which said design layer is formed. 
     
     
       6. The heat transfer recording medium of claim 1, further comprising an adhesive layer formed between said substrate and said transparent protective layer, and said design layer is formed between said adhesive layer and said transparent protective layer. 
     
     
       7. A heat transfer recording medium comprising: a substrate having items of information recorded on a surface thereof by heat transfer;   a transparent protective layer provided on at least a portion of the thus recorded surface of said substrate; and   an adhesive layer formed between said substrate and said transparent protective layer, wherein said adhesive layer provides means for providing security against counterfeiting, wherein said adhesive layer contains a photosensitive material which does not substantially conceal said information.   
     
     
       8. The heat transfer recording medium of claim 7, wherein said photosensitive material comprises at least one member selected from the group consisting of a transparent pigment, a dye, a fluorescent dye, an infrared absorber, a fluorescent brightener, and an ultraviolet absorber. 
     
     
       9. A heat transfer recording medium comprising: a substrate having items of information recorded on a surface thereof by heat transfer; and   means for providing security against counterfeiting comprising a transparent protective layer provided on at least a portion of the thus recorded surface of said substrate, said transparent protective layer containing a photosensitive material which does not substantially conceal said information.   
     
     
       10. The heat transfer recording medium of claim 9, wherein said photosensitive material comprises at least one member selected from the group consisting of a transparent pigment, a dye, a fluorescent dye, an infrared absorber, a fluorescent brightener, and an ultraviolet absorber. 
     
     
       11. A heat transfer recording medium comprising: a substrate having items of information recorded on a surface thereof by heat transfer; and   means for providing security against counterfeiting comprising a transparent protective layer provided on at least a portion of the thus recorded surface of said substrate through an adhesive layer, said transparent protective layer comprising an uneven layer.   
     
     
       12. The heat transfer recording medium of claim 11, wherein said uneven layer comprises at least one of an uneven luster, an uneven profile, an uneven thickness, an uneven surface form, and an uneven coloration.